The Pisha sandstone area in the Yellow River Basin is one of the regions with the most severe soil erosion in China and globally, and its erosion is particularly challenging to control. W-OH, a hydrophilic polyurethane material, possesses controllable degradation properties. It can react with water to achieve soil stabilization and erosion resistance during the curing process. The material has been successfully utilized in erosion control in Pisha sandstone areas. This study aims to investigate the impact of W-OH material on water/fertilizer retention and plant growth through experiments on soil hardness, permeability, soil evaporation, soil column leaching, pot tests, and a small-scale demonstration in practical engineering applications. The results indicate that different concentrations of W-OH solution can effectively permeate Pisha sandstone, solidifying the particles to create a flexible and porous consolidation layer on the surface with a specific depth. As the W-OH concentration (3%, 4%, and 5%) increases, the harnesses of the consolidation layer also increase but remain below 1.5 kPa, which does not impede plant root growth. The soil evaporation rate decreased by approximately 45.2%, 45.8%, and 50.3% compared to the control group. The reduction rates of cumulative total nitrogen (TN) content are around 43.57%, 48.14%, and 63.99%, and, for cumulative total phosphorus (TP), are approximately 27.96%, 45.70%, and 61.17% under the 3%, 4%, and 5% concentrations of W-OH solution, respectively. In the pot tests, concentrations of W-OH solution below 5% are suitable for germination and growth of monocotyledons, while the optimal concentration for dicotyledons is around 3%. In the demonstration, the vegetation coverage of the treated gully increases by approximately 11.35%. This research offers a promising and effective approach to enhance ecological restoration in Pisha sandstone areas.

Rocky desertification, a severe form of land degradation in tropical and subtropical regions driven by vegetation loss and soil erosion, poses significant ecological and economic challenges. Field trials in Fengshan County, Guangxi, China, evaluated the efficacy of NPK compound fertilizers, slow-release fertilizers, and bio-organic fertilizers on soil rehabilitation, microbial diversity, and the growth of Mahonia fortunei, a key species for ecological restoration and understory cash crop cultivation. The results demonstrated the bio-organic fertilizer’s superiority in soil regeneration, increasing organic matter by 30.4% (Bolin), 15.73% (Longlai), and 21.83% (Longlei) compared to NPK compound fertilizers, alongside elevating the total nitrogen (reaching 19.4 g/kg in Bolin) and phosphorus (85.45% higher in Bolin). Bio-organic fertilizer increased enzyme activities by 27–202% and enhanced microbial diversity, notably Proteobacteria and Actinobacteria. Slow-release fertilizers maximized micronutrient availability (e.g., Cu increased by 151.65% in Bolin) and improved plant growth, achieving peak Mahonia fortunei (Lindl.) Fedde height (3.62 cm, increasing 9.04%) and ground diameter (4.5 cm, increasing 18.42%) in Longlei compared to NPK compound fertilizers. Regional variability highlighted the bio-organic fertilizer’s dominance in soil fertility metrics, while slow-release formulations excelled in micronutrient enrichment and plant performance. NPK compound fertilizers exhibited the lowest efficacy, potentially exacerbating soil degradation. This study advocates integrating bio-organic fertilizers for soil regeneration with targeted slow-release applications for crop productivity, particularly in understory cash crop systems. Such a dual approach bridges ecological restoration with economic resilience in karst ecosystems, offering scalable solutions for global rocky desertification mitigation.

Rocky desertification is a form of land degradation occurring in tropical and subtropical regions, characterized by the destruction of vegetation and soil erosion caused by natural or anthropogenic factors, resulting in extensive areas of exposed bedrock. Field tests were conducted in three townships—Bolin, Longlai, and Longlei—within Fengshan County, Guangxi Zhuang Autonomous Region, China, to evaluate the effects of various fertilizers (compound fertilizers, slow-release fertilizers, and bio-organic fertilizers) on soil fertility, enzyme activity, bacterial diversity, and the growth performance of Mahonia fortunei (Lindl.) Fedde, aiming for ecological restoration and economic development. The findings indicated that the use of bio-organic fertilizers significantly enhanced soil fertility and enzyme activities, specifically urease, sucrase, and acid phosphatase, followed by slow-release fertilizers, and subsequently compound fertilizers. In comparison to the use of compound fertilizers, bio-organic fertilizers can enhance the organic matter content by 30.4%, 15.73%, and 21.83%, and the total nitrogen content by 19.4, 3.82, and 2.66 g/kg in the Bolin, Longlai, and Longlei regions, respectively. In the Bolin and Longlai regions, the utilization of bio-organic fertilizer yielded the maximum total phosphorus concentration, surpassing compound fertilizer by 85.45% and 53.37%, respectively. In the Longlei region, the total phosphorus concentration in the soil was about equivalent to that of compound fertilizer and bio-organic fertilizer, measuring 1.107 and 1.113 g/kg, respectively. Furthermore, the soil's available nitrogen, phosphorous, and potassium reached their peak levels when bio-organic fertilizers were applied. Urease activity increased by 181.82%, 29.29%, and 25.83%, while sucrase activity rose by 201.52%, 33.13%, and 26.22%, respectively, compared to the administration of compound fertilizer. The activity of acid phosphatase increased by 27.85%, 25.59%, and 40.49%, individually, when compared to the application of compound fertilizer. Unlike compound fertilizer, bio-organic fertilizer improved the diversity and abundance of beneficial soil microorganisms while promoting the growth of Mahonia fortunei (Lindl.) Fedde. In Bolin, Longlai, and Longlei, the concentrations of Boron (B), Copper (Cu), Zinc (Zn), and Iron (Fe) in the soil peaked with the application of slow-release fertilizers. Specifically, the Cu content increased by 151.65%, 69.97%, and 24.51%, respectively, in comparison to the use of compound fertilizers; the levels of these micronutrient elements were more comparable when bio-organic fertilizers and compound fertilizers were utilized. In the Longlei region, the use of slow-release fertilizers resulted in Mahonia fortunei (Lindl.) Fedde achieving a maximum plant height and ground diameter of 3.62 cm and 4.5 cm, respectively, surpassing the measurements obtained with compound fertilizer by 9.04% and 18.42%. This research illustrated the application of bio-organic fertilizer and slow-release formulations. Fertilizer significantly contributed to the amelioration of rocky desertification and the enhancement of vegetation, thereby offering a more effective solution for the restoration of rocky desertification flora, particularly for the cultivation of understorey cash crops.